Catalyst component for use in the polymerization of α-olefins and a method of using the same

ABSTRACT

A supported titanium catalyst component is produced by cogrinding in the presence of an ethylenically unsaturated hydrocarbon an organo aluminum catalyst component with a supported titanium (IV) halide on a magnesium halide until the intensity of the 14.8° and 30.2° x-ray diffraction peak of magnesium halide are reduced in intensity. The resulting supported titanium halide catalyst component, when employed with an organo aluminum catalyst component to form a catalyst system is highly useful for the stereoregular polymerization of α- olefins as well as the copolymerization of α-olefins.

BACKGROUND OF THE INVENTION

This invention relates to an improved catalyst component and a catalystsystem for use in the polymerization of α-olefins and a method of usingthe same, and more particularly, this invention pertains to a catalystcomponent for use in the polymerization of α-olefins, wherein theimproved catalyst component is obtained by adding a desired quantity ofan organo aluminum compound to a supported titanium (IV) halide for thepolymerization of α-olefins, subjecting the mixture to a mechanicalgrinding treatment in the presence of a desired quantity of anethylenically unsaturated hydrocarbon and in a preferred embodiment,subjecting further to removal of the hydrocarbon and to a mechanicalgrinding treatment. The invention further pertains to a catalyst systemcomprising the improved catalyst component and an organoaluminumcocatalyst, and a process for the polymerization of α-olefins using thecatalyst system comprising the improved catalyst component, whereby theparticle property, stereoregularity of the polymer are improved andcatalyst activity during polymerization is improved.

Of late, various efforts have been made in the stereoregularpolymerization of α-olefins using a catalyst system comprising asupported titanium halide catalyst component and an organo aluminumcatalyst component.

For the preparation of a supported titanium catalyst component in such acase, there has been proposed a method comprising ball milling anhydrousmagnesium chloride, an organic acid ester and silicon chloride andcontacting the resulting support with liquid titanium tetrachloride withheating to thus support the titanium component (Japanese patentapplication (OPI) No. 16,986/1973 Published Mar. 3, 1973). The inventorshave also proposed a method comprising ball milling anhydrous magnesiumchloride, an organic acid ester and titanium tetrachloride and treatingthe co-ground product with a hydrocarbon solution of hexachloroethane(U.S. patent application Ser. No. 29,081, filed Apr. 11, 1979), a methodcomprising ball milling anhydrous magnesium chloride, an organic acidester, titanium tetrachloride and hexachloroethane (U.S. patentapplication Ser. No. 29,083, filed Apr. 11, 1979) and a methodcomprising subjecting the co-ground product to an activation treatmentwith a hydrocarbon solution of hexachloroethane (U.S. patent applicationSer. No. 29,082, filed Apr. 11, 1979).

However, these methods having a grinding step yield catalysts having awide particle size distribution. When α-olefins are polymerized using acatalyst having a wide particle size distribution, the resultingpolymers also manifest a wide particle size distribution and the finelypowdered polymers cause clogging of a filter cloth. This is anundesirable result in the practice on a commercial scale.

In order to prevent formation of a fine powder polymer, it is possibleto employ a method comprising sieving a ground catalyst product andusing the obtained catalyst having a desired particle size distribution.This method, however, results in a lowered yield of titanium catalystand high cost.

For the purpose of preparing a titanium catalyst component with a narrowparticle size distribution, there has also been proposed a methodcomprising preparing magnesium chloride support with a relativelyuniform particle size and immersing the magnesium chloride in titaniumtetrachloride, followed by heating (Japanese patent application (OPI)Nos. 65,999/1974, published June 26, 1974 and 38,590/1977, publishedMar. 25, 1977). In accordance with this method, a special step for thepreparation of the support is required and there is only obtained aproduct having a low stereoregularity.

Japanese patent application (OPI) Nos. 30,681/1978, published Mar. 25,1978, published Mar. 22, 1978 describes a so-called double stageprocess, i.e., comprising an initial polymerization at a low temperatureand a real polymerization, whereby the polymerization activity,stereoregularity and bulk density are improved, but this process iscarried out by solution polymerization, not by polymerization in aliquid monomer.

In the prior art technique as set forth above, it is impossible toobtain a supported titanium (IV) catalyst component having asatisfactorily high activity, excellent durability of activity duringpolymerization, high stereoregularity and which is capable ofsuppressing formation of a fine powder polymer in bulk polymerization,and when using this catalyst component, the polymer yield per titaniumalthough is sufficiently high, the polymer yield per weight of thecatalyst (including the support) is not sufficient so as to be able toeliminate the ash removal step.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a supported titaniumcatalyst component and catalyst system having a high polymerizationactivity, excellent durability of activity during polymerization, highstereoregularity and capable of suppressing formation of polymer powderfines in the polymerization of α-olefins and a process for thepolymerization of α-olefins using the same, which process is favorableon a commercial scale.

In accordance with the present invention, there is provided a catalystcomponent and catalyst system for use in the polymerization ofα-olefins, the catalyst component being obtained by adding an organoaluminum catalyst component, e.g., an organo aluminum compound or amixture or adduct of an organo aluminum compound and electron donativecompound in a desired quantity to a supported titanium catalystcomponent on a support of magnesium chloride, prepared from a magnesiumhalide, tetravalent titanium halide, electron donating compound (Lewisbase) and optionally one or more fourth components selected from thegroup consisting of organo halogen compound and halogen-containingcompounds of Group IVa elements of Periodic Table except carbon andsubjecting the mixture to a mechanical grinding treatment in thepresence of an ethylenically unsaturated hydrocarbon. In accordance withanother embodiment of the invention, the unsaturated hydrocarbonremaining after the initial grinding is removed and the mixture issubjected to a mechanical grinding treatment in an atmosphere of inertgas. In accordance with yet another embodiment of the invention there isprovided a process for the homopolymerization of α-olefins or thecopolymerization thereof with ethylene or other α-olefins using the thusobtained catalyst component in combination with an organo aluminumcocatalyst with the foregoing advantages or effects.

The important feature of the present invention comprises a supportedtitanium catalyst component which is subjected to mechanical grinding inthe presence of an organo aluminum catalyst component and ethylenicallyunsaturated hydrocarbon and, in general, the mechanical grinding iscarried out with the polymerization of the ethylenically unsaturatedhydrocarbon to thus obtain a catalyst component for the polymerizationof α-olefins with a decreased amount of fine particles.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be illustrated in order and in detail.

I. Catalyst component and treating agent

(1) Magnesium halide

The magnesium halide, in particular, anhydrous magnesium dihalide usedin the present invention includes MgCL₂, MgBr₂ and MgI₂. MgCl₂ ispreferably employed. These anhydrous magnesium dihalides can be thosesynthesized by any methods and commercially sold compounds can be used.The magnesium dihalide should be substantially anhydrous, the presenceof water being allowed to such an extent that the catalytic performanceis not affected. Usually, the commercially sold anhydrous magnesiumdihalide, prior to use, is subjected to a dehydration treatment inconventional manner, for example, by calcining at a temperature of 100°C. to 400° C. under reduced pressure for 1 to 10 hours.

(2) Titanium (IV) halide

Typical examples of tetravalent titanium halide used in the presentinvention are TiCl₄, TiBr₄ and TiI₄. However, it is not always necessarythat all the anions be halogens, a part thereof can be substituted byalkoxy, acyloxy or alkyl groups. Preferably TiCl₄ is employed inaccordance with the present invention.

(3) Electron donative compound (Lewis base)

Examples of the electron donative compound used in the present inventionare organic carboxylic acids, organic carboxylic acid esters, alcohols,ethers, ketones, amines, amides, nitriles, aldehydes, alcoholate,phosphorus, arsenic and antimony compounds combined with organic groupsthrough carbon or oxygen, phosphoamides, thioethers, thioesters andcarbonic acid esters. In particular, organic acid esters are preferablyused.

The organic acid esters are esters formed by condensation of saturatedor unsaturated aliphatic, alicyclic and aromatic mono- or polycarboxylicacids and aliphatic, alicyclic and araliphatic mono- or polyols.Illustrative examples of these esters are butyl formate, ethyl acetate,butyl acetate, ethyl acrylate, ethyl butyrate, isobutyl isobutyrate,methyl methacrylate, diethyl maleate, diethyl tartrate, ethylhexahydrobenzoate, ethyl benzoate, ethyl p-methoxybenzoate, methylp-methylbenzoate, ethyl p-tert-butylbenzoate, dibutyl phthalate,diallkyl phthalate and ethyl α-naphthoate. The organic acid esters arenot intended to be limited to these examples. Above all, alkyl esters ofaromatic carboxylic acids, in particular, C₁ to C₈ alkyl esters ofnucleus-substituted benzoic acids such as p-methylbenzoic acid andp-methoxybenzoic acid, or benzoic acid are preferably used.

(4) Fourth component (organo halogen compounds and halogen-containingcompounds of Group IVa elements of Periodic Table except carbon orhaving the skeletons of the elements)

Typical examples of the organo halogen compound used optionally as thefourth component for the preparation of the supported titanium (IV)halide on a magnesium halide according to the present invention aremono- and polyhalo-substituted products of saturated or unsaturatedaliphatic, alicyclic and aromatic hydrocarbons. Illustrative, butnon-limiting examples of aliphatic compounds are methyl chloride, methylbromide, methyl iodide, methylene chloride, methylene bromide, methyleneiodide, chloroform, bromoform, iodoform, carbon tetrachloride, carbontetrabromide, carbon tetraiodide, ethyl chloride, ethyl bromide, ethyliodide, 1,2-dichloroethane, 1,2-dibromoethane, 1,2-diiodoethane,methylchloroform, methylbromoform, methylioodoform,1,1,2-trichloroethylene, 1,1,2-tribromoethylene,1,1,2,2-tetrachloroethane, hexabromoethane, n-propyl chloride,1,2-dichloropropane, hexachloropropylene, octachloropropane,decabromobutane and chlorinated paraffins. Illustrative of alicycliccompounds are chlorocyclopropane, tetrachlorocyclopentane,hexachloropentadiene and hexachlorocyclohexane. Illustrative of aromaticcompounds are chlorobenzene, bromobenzene, o-dichlorobenzene,p-dichlorobenzene, hexachlorobenzene, benzotrichloride andp-chlorobenzotrichloride. In addition to these halo substitutedhydrocarbons, it is possible to use halo substituted oxygen-containingcompounds, for example, hexachloroacetone, chloro acetic acid ester,trichloroacetic acid esters and the like. Above all, polyhalosubstituted products, in particular, polychloro substituted products ofaliphatic hydrocarbons are preferably used, and most preferably, carbontetrachloride, 1,1,2-trichloroethylene, 1,1,2,2-tetrachloroethane,hexachloroethane and octachloropropane are used.

As the halogen-containing compound of Group IVa elements of PeriodicTable, except carbon, having the skeletons of such Group IVa elements,which can be used as the fourth component according to the presentinvention, for example, are halogen compounds of silicon, germanium,tin, lead or their homologues.

Typical examples of the halogen compound of silicon represented by thegeneral formula Si_(m) X_(2m+2), (wherein m is generally an integer of 1to 10), are polyhalosilanes such as tetrahalosilanes, hexahalodisilanes,octahalotrisilanes, decahalotetrasilanes, dodecahalopentasilanes,tetradecahalohexasilanes, docosahalodecasilanes and the like. In thesepolyhalosilanes, the halogen atoms may be same or different. Preferablesilanes employed in accordance with this invention are tetrahalosilanescorresponding to m=1 in the above general formula, for example,tetrachlorosilane, tetrabromosilane, tetraiodosilane,trichlorobromosilane, trichloroiodosilane, trichlorofluorosilane,dichlorodibromosilane, dichlorodiodosilane, chlorotribromosilane,chlorotriiodosilane and tribromoiodosilane. Tetrachlorosilane is mostpreferable because of being readily obtainable on a commercial scale.Moreover, a part of the halogens in the above described halosilanehomologues can be replaced by one or more of alkyl, aryl, aralkyl,vinyl, alkoxy and acyl groups.

Typical examples of the halogen compound of germanium represented by thegeneral formula GeX_(m), wherein X is a halogen and m is an integer of 2or 4, are GeCl₂, GeBr₂, GeI₂, GeCl₄, GeBr₄ and GeI₄ and particularly,GeCl₂ and GeCl₄ are preferably used. A part of the halogens in the abovedescribed halogermanium compounds can be replaced by one or more ofalkyl, aryl, aralkyl, vinyl, alkoxy and acyl groups.

Typical examples of the halogen compound of tin represented by thegeneral formula SnX_(m), wherein X and m have the same meanings asdescribed above, are SnCl₂, SnBr₂, SnI₂, SnCl₄, SnBr₄, SnI₄, SnCl₃ Br,SnCl₂ Br₂, SnBr₃ Cl, SnBr₂ I₂ and SnCl₂ I₂, and particularly, SnCl₂ andSnCl₄ are preferably used. A part of the halogens in the above describedhalotin compounds can be replaced by one or more of alkyl, aryl,aralkyl, vinyl, alkoxy and acyl groups.

Typical examples of the halogen compound of lead represented by thegeneral formula PbX_(m), wherein X and m have the same meanings asdescribed above are PbCl₂, PbCl₄, PbBr₂, PbBr₄, PbI₂ and PbI₄ andparticularly, PbCl₂ and PbCl₄ are preferably used. A part of thehalogens in the above described halolead compounds can be replaced byone or more of alkyl, aryl, aralkyl, vinyl, alkoxy and acyl groups.

Of the halogen compounds of Group IVa elements of Periodic Table as setforth above, organo halogen compounds and halosilane compounds are mostpreferably used.

The various halo compounds can also be used individually or incombination.

(5) Organo aluminum compound

The organo aluminum compound used in the present invention is an organoaluminum compound represented by the general formula R_(m) AlX_(3-m),wherein R is an alkyl group or aryl group, X is a halogen anion and m isa numeral of 1<m≦3, or a mixture or complex compound thereof. Forexample, trialkylaluminums are used, and in addition to thetrialkylaluminums, there are preferably used as an organo aluminumcompound to be used jointly with the trialkylaluminums, alkylaluminumcompounds having 1 to 18 carbon atoms, in particular, 2 to 6 carbonatoms, such as dialkylaluminum monohalies, monoalkylaluminum dihalidesand alkylaluminum sesquichloride, mixtures or complex compounds thereof.

Examples of the trialkylaluminum are trimethylaluminum,triethylaluminum, tripropylaluminum and triisobutylaluminum. Examples ofthe dialkylaluminum monohalide are dimethylaluminum chloride,diethylaluminum chloride, diethylaluminum bromide, diethylaluminumiodide and diisobutylaluminum cloride. Examples of the monoalkylaluminumdihalide are methylaluminum dichloride, ethylaluminum dichloride,ethylaluminum dibromide, ethylaluminum diiodide and isobutylaluminumdichloride. Example of the alkylaluminum sesquihalide is ethylaluminumsesquichloride. In particular, it is preferable to use triethylaluminum,triisobutylaluminum and as one to be used jointly with them,diethylaluminum chloride and ethylaluminum sesquichloride, or mixturesor complex compounds thereof, because these compounds are readilyobtainable commercially and exhibit excellent effects.

(6) Ethylenically unsaturated hydrocarbon

The ethylenically unsaturated hydrocarbon used for the preparation ofthe catalyst component for the polymerization of α-olefins according tothe present invention includes C₂ -C₂₀ aliphatic mono-α-olefins such asethylene, propylene, butene-1, pentene-1, hexene-1, octene-1 and4-metylpentene-1, C₈ -C₁₀ aromatic substituted olefins such as styrene,α-methylstyrene, p-methylstyrene and divinylbenzene, alicyclicsubstituted olefins such as vinylcyclohexane and vinylcyclohexene, andalicyclic unsaturated hydrocarbons such as norbornene,4-methylnorbornene and norbornadiene. Above all, aliphaticmono-α-olefins are preferably used. The α-olefin used herein may be sameas or different from that used in the stereoregular polymerization to beeffected later, but it is more preferable to use the same α-olefin asthat of the stereoregular polymerization or the component used in thecopolymerization.

(7) Hydrocarbon

The hydrocarbon which can be used, for example, in the preparation ofthe supported titanium halide or in the polymerization of α-olefinsaccording to the present invention is dehydrated in conventional mannerand includes aliphatic hydrocarbons having 3 to 20 carbon atoms such aspropane, butane, isobutane, pentane, n-hexane, n-heptane, isooctane,decane and liquid paraffins, alicyclic hydrocarbons having 5 to 12carbon atoms such as cyclopentane, cyclohexane, methylcyclohexane,ethylcyclohexane, decalin and dimethyldecalin, and aromatic hydrocarbonshaving 6 to 12 carbon atoms such as benzene, toluene, o-xylene,p-xylene, m-xylene, mixed xylenes, ethylbenzene, dimethylnaphthalene andtetralin, gasoline and kerosene.

II. Preparation of supported titanium (IV) halide on magnesium halide

The present invention can be applied to titanium (IV) halides supportedon magnesium halides prepared by various methods (which will hereinafterbe referred to as "titanium-containing solid"). The embodiments thereofwill be given in the following, but the present invention is notintended to be limited thereby.

(1) A titanium-containing solid obtained by subjecting a systemcomprising (a) a magnesium halide, (b) tetravalent titanium halide, (c)electron donative compound and (d) fourth component to a co-grindingand/or contacting treatment,

(2) A titanium-containing solid obtained by treating thetitanium-containing solid obtained in (1) with a hydrocarbon and/orfourth component,

(3) A titanium-containing solid obtained by subjecting a systemcomprising (a) a magnesium halide, (c) electron donative compound and(d) fourth compound to a co-grinding and/or contacting treatment toprepare a support composition; contacting the support composition with atetravalent titanium halide under heating in the presence or absence ofa solvent, and then treating with a hydrocarbon and/or fourth componentunder heating or at room temperature,

(4) A titanium-containing solid obtained by subjecting a systemcomprising (a) a magnesium halide, (b) tetravalent titanium halide and(c) electron donative compound to a co-grinding and/or contactingtreatment,

(5) A titanium-containing solid obtained by treating thetitanium-containing solid of (4) under heating with a hydrocarbon and/orthe fourth component (d) and

(6) A titanium-containing solid obtained by co-grinding (a) a magnesiumhalide and (b) tetravalent titanium halide to obtain atitanium-containing solid and further treating the titanium-containingsolid under heating with a hydrocarbon and/or electron donative compound(c).

For example, the titanium-containing solid (1) will now be illustratedin detail.

The supported titanium catalyst component is obtained by subjecting (a)a anhydrous magnesium dihalide, (b) tetravalent titanium halide, (c)electron donative compound and (d) fourth component to a co-grindingand/or contacting treatment in various manners. That is, for theproduction thereof, adding methods and contacting orders or proceduresof these compounds can be varied suitable, but it is required that allof these compounds are finally brought into contact with each other. Theco-grinding and/or contacting treatment is preferably carried out as tothe following systems each comprising a combination of these compoundsand, more preferably, it is carried out by mechanical grinding using avibration mill, ball mill, and the like.

(i) mixtures of (a), (b), (c) and (d),

(ii) mixtures of (b), (d) and a complex (e) formed previously from (a)and (c),

(iii) mixtures of (a), (d) and a complex (f) formed previously from (b)and (c),

(iv) mixtures of (b), (c) and a complex (g) formed previously from (a)and (d),

(v) mixtures of (f) and (g),

(vi) mixtures of (d), (f) and (d),

(vii) mixtures of (a), (f) and (d), and

(viii) mixtures of (d) and a complex (h) formed previously from (a) and(f). Above all, a method of forming previously a complex is preferablyselected from wet process of dry process mechanical grinding treatmentsand contacting treatments in the presence or absence of a solvent atroom temperature or with heating, and each of the mixtures can beprepared by mixing the components at a time or in a suitable order.

In accordance with the present invention, it is necessary to effectgrinding until there is produced a change of intensity in the peaks of14.8° (strong) and 30.2° (middle) of the characteristic peaks (2θ) inthe X-ray diffraction (45 KV×45 mA, CuK source, Ni filter) or anhydrousmagnesium chloride used as a support, although the time of mechanicalgrinding depends upon the grinding efficiency, grinding system, grinderstructure, quantity of starting materials charged, voids, temperature,etc. More preferably, the grinding is carried out to such an extent thatthe peak of 14.8° becomes dull with an increased width and the 30.2°peak loses its intensity to a great extent. For example, inthe case ofcharging 10 to 50 g of a mixture in a vibration mill of 300 ml in innervolume, having 100 steel balls of 10 m/m in diameter and grinding at avibration width of 1 to 3 m/m and a vibration number of 1400 rpm, thegrinding time is usually 1 to 200 hours, preferably 10 to 100 hours.

The quantity of a titanium halide on the support is preferably 0.1 to10% by weight as titanium metal. An electron donative compound ispreferably used in a proportion of 0.1 to 10 mols, particularly, 0.5 to5 mols to 1 gram atom of the supported titanium metal and a fourthcomponent is preferably used in a proportion of 1 to 100% by weight,particularly, 5 to 50% by weight to the anhydrous magnesium halide.

According to the above described method, a complex composed of (a), (b),(c) and (d) can be obtained in the form of a flowable solid even if thefourth component used is liquid.

The supported titanium catalyst component obtained in this way does nothave a large surface area and a large pore volume, that is, it has asurface area of about 5 to about 15 m² /g and pore volume of about 0.01to about 0.02 cc/g, but when used in combination with an organo aluminumcatalyst component, it is capable of giving a high stereoregularity withholding a high polymerization activity in the homopolymerization ofα-olefins or the copolymerization thereof with ethylene or otherα-olefins.

The titanium-containing solid prepared by the foregoing procedurecontains fine particles. When polymerization of α-olefins is carried outusing a catalyst system comprising this titanium-containing solid as atitanium catalyst component and an organo aluminum catalyst component,therefore, the resulting poly-α-olefins contain a large quantity offinely powdered polymers of 100 mesh or less. In the case of using thetitanium-containing solids (2) to (6), the particle size and particlesize distribution also cause the production of finely powdered polymersof 100 mesh or less in a considerable proportion.

III. Polymerizing and grinding treatment

The essence of this invention which results in the elimination ofpolymer fines is the grinding treatment of the above describedtitanium-containing solid in the presence of an organo aluminum compoundand an ethylenically unsaturated hydrocarbon.

The grinding treatment in accordance with the invention is a treatmentwherein the titanium-containing solid and organo aluminum catalystcomponent are subjected to mechanical grinding in the presence of anethylenically unsaturated hydrocarbon. During this grinding treatment,the ethylenically unsaturated hydrocarbon is polymerized andsimultaneously ground. The ethylenically unsaturated hydrocarbon isdecreased with the progress of the mechanical grinding, so it isnecessary to add a previously predetermined quantity of it or to fill upsuitably during the mechanical grinding. In accordance with onepreferred embodiment of the invention, a catalyst component for thepolymerization of α-olefins, having more excellent properties, can beobtained by, after the mechanical grinding in the presence of anethylenically unsaturated hydrocarbon, removing the hydrocarbon andfurther carrying out a mechanical grinding treatment in vacuum or in anatmosphere of inert gas.

A non-limiting embodiment of the present invention will in detail beillustrated, for example, as to the titanium-containing solid preparedby the method of II-(1) described above.

When or after a magnesium halide (a), tetravalent titanium halide (b),electron donative compound (c) and organo halogen compound (d) arefinally mixed, a predetermined quantity of one or more of the organoaluminum compounds is added and the mixture is subjected to a mechanicalgrinding treatment when or after a predetermined quantity of theethylenically unsaturated hydrocarbon of I-(6) is added to the system ata time or intermittently and polymerized, thus obtaining a catalystcomponent for the polymerization of α-olefins with less fine particles.

If the additive amounts of the organo aluminum compound andethylenically unsaturated hydrocarbon are too large, the flowability ofa titanium catalyst component is undesirably greatly reduced, while iftoo small, fine particles cannot be reduced.

The additive amount of the organo aluminum compound can widely beselected as far as the above described requirement is satisfied,however, it is generally 0.05 to 5 mols, preferably 0.1 to 1.0 mol andmost preferably 0.3 to 0.7 mol per 1 gram atom of titanium. During thesame time, it is not always essential to use an electron donatingcompound with the organo aluminum compound, but it is desirable to useit in a proportion of 0.1 to 10 mols, preferably 0.5 to 2 mols to 1 molof the organo aluminum compound.

In the addition of the organo aluminum compound and electron donativecompound, a solvent as shown in I-(7) can be used, but it isadvantageous to use no solvent so as to simplify subsequent processings.These two materials can be added individually, but it is convenient toadd them after preforming an adduct thereof.

For the purpose of mixing and dispersing evenly the organo aluminumcatalyst component with the titanium-containing solid, after added, itis desirable to effect a mechanical mixing operation. This mixing can besufficiently accomplished in 30 minutes, for example, by the use of avibration mill as set forth above.

The quantity of ethylenically unsaturated hydrocarbon to be used can bevaried widely within such a range that the supported titanium catalystcan give a desired flowability and particle property, but it isordinarily 0.5 to 100% by weight, preferably about 1 to 20% by weight,most preferably 3 to 10% by weight based on the catalyst solid. Feedingof an ethylenically unsaturated hydrocarbon can be carried out all atonce or intermittently in the form of either gas or liquid and in thepresence or absence of a molecular weight regulator such as hydrogen oran inert gas, optionally selecting suitable temperature and pressurecondition. These conditions can suitably be combined considering theconvenience of operations.

The polymerization can be carried out with suitable agitation, but it isdesirable in order to achieve the advantages or effects of the presentinvention to a maximum extent to effect the polymerization withmechanically grinding, for example, using a vibration mill or ball mill.When using the vibration mill, for example, the time for thepolymerizing and grinding treatment is sufficiently 5 hours or less.Through this treatment, a yellow titanium-containing solid is changed toa color of gray green. In the thus obtained titanium-containing solid,the surface area and pore volume are rather decreased than before thetreatment, but there is found no remarkable change in X-ray diffractionpattern in comparison with before the treatment.

When the titanium-containing solid obtained by this treatment issubjected to a particle size measuring device of light transmissiontype, it has a larger average particle size than the ground product ofII and titanium halide and a largely decreased content of fine particlesof 10 microns or less.

It has been surprisingly discovered that when the polymerization iscarried out without the mechanical grinding, such an effect is not foundor when a polymer and a titanium-containing solid obtained by theprocedure II are subjected to mechanical grinding in a time similar tothe present treatment, both the materials remain as separate particleswith fine particles not being substantially eliminated.

Therefore, it is not considered that according to the present treatment,the finely powdered titanium-containing solid adheres only to thepolymer formed in the system by the grinding treatment to increase theparticle diameter. It is not clear what structure the ground product inthe present treatment has, but in view of the above described results ofthe comparative examples, it can be assumed that a polymer acting as abinder is formed on active points dispersed microscopically on a supportand thus the polymer is highly dispersed in microcrystalline order sothat the fine particles are effectively aggregated during the grindingstep consisting of repetitions of grinding and aggregating and thepolymer itself is hardly aggregated to each other. Thus, there can beobtained a titanium-containing solid which has a suitable particle sizeand excellent flowability and is free from being massive.

When homopolymerization of α-olefins or copolymerization thereof withethylene or other α-olefins is carried out in the presence of a catalystcomprising, in combination, the titanium-containing solid subjected tothis treatment as a titanium catalyst component and an organo aluminumcatalyst component such as described above, formation of finely powderedpolymer is suppressed to a greater extent and the polymerizationactivity is held, i.e., the polymer yield is increased with the passageof time, as compared with the case of using the titanium catalystcomponent free from this treatment.

IV. Mechanical grinding treatment under ethylenically unsaturatedhydrocarbon-removed state

When the titanium-containing solid after the grinding treatment of IIIis further subjected to removal of the ethylenically unsaturatedhydrocarbon and to further mechanical grinding for a suitable period oftime in vacuum or in a gaseous atmosphere or inert gas, for example,lower saturated hydrocarbons such as methane, ethane, propane andbutane, nitrogen, argon and helium in the presence or absence of aninert solvent such as described in I-(7), not only the polymerizationactivity and stereoregularity are improved to a greater extent than inthe case of using the titanium catalyst component obtained by thetreatment III, but also the polymerization activity of the finallyprepared catalyst is increased. It is unexpected that the polymer yieldis increased with the passage of time, the stereoregularity is scarecelylowered during the same time and there is formed little fine powderpolymer with a particle size of 100 mesh of less.

Furthermore, it is found that even if an aluminum catalyst component pera titanium catalyst component is decreased to great extent as comparedto that employed in the prior art, a sufficiently high polymerizationactivity and stereoregularity are held or increased.

The time required for the present treatment is not limited, but, for thecommercial convenience, it is preferably selected from 30 minutes to 2hours. The titanium-containing solid obtained by this treatment showsthe similar surface area and pore distribution to thetitanium-containing solid obtained by the treatment III and there isfound no marked difference in the X-ray diffraction patterns. The colorof the powder is gray green or that tinged somewhat with yellow.Macroscopic differences from the product of III consist in that theparticles exhibit a better flowability and the presence of fineparticles with a particle diameter of 10 microns or less can beneglected.

The reason why the above described effects or advantages are obtained isnot clear, but these effects are possibly due to that the polymer as abinder is more highly dispersed in microcrystalline order withoutinfluences due to the new growth than in the polymerizing and grindingtreatment to thus aggregate the fine particles effectively, and newactive points are further formed by the grinding. This cannot beachieved by polymerizing an ethylenically unsaturated hydrocarbon on atitanium-containing solid only or by subjecting a polymer andtitanium-containing solid to a grinding treatment for a period of timecorresponding to the sum of III and IV only.

That is to say, when polymerization of α-olefins is carried out in thepresence of a catalyst comprising the titanium catalyst componentobtained by this treatment and an organo aluminum catalyst component, anumber of advantages are obtained that the yield of poly-α-olefins pertitanium and per whole catalyst weight is increased with the passage oftime, removal of halogens or aluminum can be made unnecessary or can belargely lightened, the stereoregularity during the same time is onlyslightly lowered and formation of a finely powdered polymer with aparticle size of 100 mesh or less is largely suppressed.

The generally used organo aluminum compound for composing an organoaluminum catalyst component used in the stereoregular polymerization ofα-olefins can be chosen from those mentioned in I-(5) and may be same asor different from that used in the polymerizing and grinding treatment.

When the above described organo aluminum compound only is used with thesupported titanium catalyst component for the polymerization ofα-olefins in the presence of a molecular weight regulator such ashydrogen, the yield of a stereoregular polymer is remarkably decreased.Therefore, as the organo aluminum catalyst component of the presentinvention, there are used complexes consisting of, in combination,organo aluminum compounds and one or more selected from the group ofelectron donating compounds described in the foregoing section of thecatalyst component.

A suitable electron donative compound may be same as or different fromthat used in the preparation of the supported titanium catalystcomponent. Their ratio is chosen within a range of 0.1 to 10 gram atoms,preferably 1 to 5 gram atoms of aluminum in the organo aluminum compoundto 1 mol of the electron donative compound. Preparation of the organoaluminum catalyst component is carried out by contacting an organoaluminum compound and electron donative compound, for example, by mixingthem at room temperature merely or while using a suitable hydrocarbon,for example, n-hexane or n-heptane as a diluent. The organo aluminumcatalyst component is ordinarily prepared before a polymerizationreaction, but, in general, it is preferably used within 1 hour after thecomplex is prepared since the stereoregularity is unfavorably affectedif it is used after storage of the complex for a long time.

The catalyst system of the present invention can be used for thepolymerization of α-olefins, in particular, for the stereospecificpolymerization of α-olefins having 3 to 6 carbon atoms, for example,propylene, butene-1, 4-methyl-pentene-1 and hexene-1 and for thecopolymerization of the above described α-olefins with each other and/orwith ethylene. This copolymerization includes random copolymerizationand block copolymerization. In the case of using ethylene as acomonomer, its proportion is generally chosen within a range of up to30% by weight, in particular, 1 to 15% by weight to α-olefins. Apolymerization reaction using the catalyst of the present invention iscarried out under the commonly used conditions.

The reaction can be carried out in any of a gaseous phase and liquidphase and for the reaction of liquid phase, any of inert hydrocarbonsand liquid monomers can be used. A suitable solvent, which can be usedin the polymerization in a solvent, is selected from the foregoinghydrocarbons. The polymerization temperature is generally -80° C. to150° C., preferably 40° C. to 100° C. The pressure ranges from 1 to 40atm, for example. Control of the molecular weight during polymerizationis carried out in conventional manner using hydrogen or other knownmolecular weight regulators. This polymerization method can be carriedout continuously or batchwise. The organo aluminum catalyst component isutilized for the polymerization reaction and further serves to catchvarious poisons introduced into the system. Thus, it is necessary tocontrol the additive quantity of the organo aluminum catalyst componentconsidering the quantities of catalyst poisons contained in α-olefins,solvents and various gases, in particular, when using a high activitycatalyst as in the present invention, and the organo aluminum catalystcomponent is ordinarily used so as to satisfy an Al/Ti atomic ratio of 1to 2000, preferably 50 to 1000 based on titanium in the supportedtitanium catalyst component.

When polymerization is carried out according to the present invention,the polymerization activity is improved and maintained with a highdurability for the passage of time, while a high stereoregularity isheld, and, consequently, the steps of removing the catalyst and removingatactic polymers becomes useless or the load thereon is markedlyreduced.

The process of the present invention is particularly important for theproduction of isotactic polypropylene, random copolymers of ethylene andpropylene and block copolymers of propylene and ethylene.

The present invention will now be illustrated in detail by the followingexamples without limiting the same, in which percents are to be taken asthose by weight unless otherwise indicated. The polymerization activityor catalyst efficiency (which will hereinafter be referred to as "C.E.")is the quantity (g) of a polymer formed per 1 g of titanium and per 1 gof whole catalyst. The heptane-insoluble component (which willhereinafter be referred to as "H.I.") to show the proportion of acrystalline polymer in the polymers means the residual quantity (% byweight) in the case of extracting the product with boiling n-heptane for6 hours by means of a Soxhlet extractor of improved type. The melt flowrate ("M.F.R.") is measured according to ASTM-D 1238.

EXAMPLE 1

(1) Preparation of titanium-containing solid

29 g (59.6%) of anhydrous magnesium chloride, 9.6 g (19.8%) of anequimolar complex of titanium tetrachloride and ethyl benzoate TiCl₄.C₆H₅ CO₂ C₂ H₅ and 8.4 g (20.6%) of hexachloroethane were charged in astainless steel (SUS 32) mill pot with an inner volume of 300 mlcarrying 100 stainless steel (SUS 32) balls with a diameter of 10 mm ina nitrogen atmosphere, which was then fitted to a shaker, followed byshaking for 61.5 hours. The obtained titanium-containing solid wasyellow and had a titanium content of 2.4%. The surface area of the solidmeasured by the BET method was 6.5 m² /g and the pore volume was 0.019cc/g. X-ray diffraction analysis (45 KV×45 mA; CuK.sub.α ray source; Nifilter) showed that the peaks of 14.8° and 34.8° of the characteristicpeaks (2θ) of anhydrous magnesium chloride became dull with increasedwidths and the peaks of 30.2° and 63° disappeared, while there wasscarcely found a change in the peak of 50.3°.

According to measurement of the particle size distribution by a lighttransmission type device, the titanium-containing solid coground by theshaking mill had a smaller particle size than the anhydrous magnesiumchloride as the starting material and there were fine particles of 10microns or less.

(2) Grinding treatment

24.0 g of the titanium-containing solid obtained by the above describedmethod, 1.20 g of triisobutylaluminum corresponding to 0.5 aluminum gramatom per 1 gram atom of the titanium and 0.91 g of ethyl benzoate beingequimolar to the triisobutylaluminum were mixed, held for 5 minutes andcharged in the above described mill pot, which was then fitted to ashaker, followed by shaking for about 10 minutes to mix evenly thetitanium-containing solid, triisobutylaluminum and ethyl benzoate. Then,the shaking was carried out for 30 minutes while introducing propyleneintermittently into the mill pot. The resulting solid was a gray greenflowable powder containing 4.5% of polypropylene and having a titaniumcontent of 2.2%.

The above described titanium-containing solid had a larger grain sizethan the titanium-containing solid obtained in (1) and the anhydrousmagnesium chloride as the starting material, and contained a very smallamount of fine particles of 10 microns or less.

Polymerization of an α-olefin using the thus obtainedtitanium-containing solid is carried out by the following procedure.60.5 mg of the above described titanium-containing catalyst component(Ti supporting ratio: 2.2%), 1 mol/1 n-heptane solution of 0.91 g oftriethylaluminum corresponding to 300 Al gram atoms per 1 gram atom ofthe titanium and 0.37 g of ethyl p-anisate corresponding to 0.29 mol per1 gram atom of aluminum in the triethylaluminum were mixed, held for 5minutes and charged in a stainless steel (SUS 32) autoclave with aninner volume of 1000 ml, equipped with a stirrer, in an atmosphere ofnitrogen. In addition, 0.6 l of hydrogen gas as a molecular weightregulator and 0.8 l of propylene were introduced under pressure into thesystem, which was then heated to 68° C., and the polymerization wascarried out for 30 minutes.

After the polymerization, the unreacted propylene was purged and 174 gof a white powdered polypropylene was obtained corresponding to C.E. ofPP (polypropylene) 130 Kg/g-Ti and PP 2870 g/g-catalyst. H.I.=92.6%, MFRof the polymer=4.1. A finely powdered polymer with a grain particle of100 mesh or less in the resulting polymer amounted to 2.9%.

When the similar polymerization operation was carried out for alengthened polymerization time of 1 hour, C.E. was PP 211 Kg/g-Ti and PP4640 g/g-catalyst and H.I. was 92.0. The proportion of a finely powderedpolymer with a particle size of 100 mesh or less was 2.5%. The amount ofthe polymer formed was markedly increased by lengthening thepolymerization time, from which it was apparent that the activity wasmaintained at a high level during the same time.

(3) Postgrinding treatment

20 g of the solid subjected to the polymerizing and grinding treatmentin (2) (titanium content: 2.2%) was taken in the mill pot and furthershaken for 1.5 hours in an atmosphere of nitrogen to effect grinding.The titanium-containing solid obtained by this treatment was a grayyellow and green powder with a higher flowability than that of (2) andwith little fine particles.

50.4 mg of the postground solid thus obtained, 0.79 g oftriethylaluminum (Al/Ti atomic ratio: 300) and 0.37 g of ethyl p-anisate(Al compound/ethyl benzoate molar ratio: 3.4) were mixed and held for 5minutes. Using the resulting titanium catalyst component with an organoaluminum catalyst component, the similar operation was carried out usingan organo aluminum catalyst component to the polymerization of thepolymerization (2).

The resulting polypropylene amounted to 211.2 g corresponding to C.E. ofPP 191 Kg/g-Ti and PP 4200 g/g-catalyst. H.I. was 94.3%. The proportionof a finely powdered polymer with 100 mesh or less was only 2%. When thesimilar operation was carried out for a lengthened polymerization timeof 1 hour, C.E. was PP 307 Kg/g-Ti and 6750 g/g-catalyst and H.I. was93.0%. A finely powdered polymer of 100 mesh or less was formed in suchan amount as could not be determined.

When the aluminum atomic ratio in the organo aluminum catalyst componentto the titanium atom in the titanium catalyst component was reduced andpolymerization was carried out for 30 minutes, C.E. was PP 253 Kg/g-Tiand PP 5560 g/g-catalyst and H.I. was 93.3.

Even when the Al/Ti atomic ratio was reduced to about 1/3 as describedabove, C.E. was improved and H.I. was not so decreased. This means thatthe content of the aluminum ash in the polymer was 1/3 or less.

COMPARATIVE EXAMPLE 1

The procedure of Example 1-(2) was repeated except using thetitanium-containing solid (Ti content: 2.4%) obtained in Example 1-(1).After the polymerization for 30 minutes, there were obtained results ofC.E. PP 131 Kg/Kg-Ti and PP 3140 g/g-catalyst, H.I. 91.2 and MFR of 3.2.The quantity of a fine powder polymer with a particle size of less than100 mesh was 9.5%.

When the polymerization time was lengthened to 1 hour, C.E. was PP 154g/g-Ti and PP 3690 g/g-catalyst and H.I. was 90.9. The quantity of afinely powdered polymer of 100 mesh or less was 9.0%.

It is apparent from these results that when the polymerizing andgrinding treatment of the present invention is carried out, thepolymerization activity is increased, and a fine powder polymer isdecreased, and when the postgrinding treatment is carried out, thepolymerization activity is further improved to a large extent, H.I. israised and a fine powder polymer is further decreased. On the otherhand, when the polymerizing and grinding treatment is not carried out asin Comparative Example, the polymerization activity per whole catalystis low and there is considerable formation of fine powder polymer.

COMPARATIVE EXAMPLE 2

20 g of the titanium-containing solid obtained in Example 1-(1) wascharged in a 300 ml round bottom glass flask equipped with a stirrer.1.00 g of triisobutylaluminum corresponding to 0.5 aluminum atom per 1 gof the titanium and 0.76 g of ethyl benzoate being equimolar to thetriisobutylaluminum were mixed, held for 5 minutes and then dropwiseadded to the titanium-containing solid over a period of 5 minutes whilerevolving the stirrer. The stirring was further continued for another 10minutes so as to thoroughly mix the components. The N₂ gas in the flaskwas then purged for 10 seconds by propylene gas and the system wasrinsed and substituted by an atmosphere of propylene, followed bypolymerization. The polymerization was carried out under a pressure ofthe atmospheric pressure plus 400 mm water column while feedingpropylene so that the flask would not be under reduced pressure even ifthe propylene was consumed by the polymerization. After 60 minutes,feeding of propylene was stopped and the system was replaced by N₂ gas.The resulting solid contained 5.8% of polypropylene and has a titaniumcontent of 2.3%.

When the similar polymerization procedure to Example 1-(2) was carriedout using the solid obtained in this way, there were obtained results ofC.E. of PP 124 Kg/g-Ti and PP 2850 g/g-catalyst and H.I. of 91.3%. Thequantity of a polymer with a particle size of 100 mesh or less was10.0%. It is apparent from this result that formation of a fine powderpolymer cannot be suppressed by the previous polymerization free from agrinding treatment only.

COMPARATIVE EXAMPLE 3

The procedure of Example 1-(1) was repeated except using 11.6 g ofanhydrous magnesium chloride (59.7%), 4.0 g of an equimolar adduct oftitanium tetrachloride-ethyl benzoate (20.7%) and 3.8 g ofhexachloroethane (19.6%). 19.4 g of the resulting titanium-containingsolid and 0.9 g of a homopolypropylene powder (H.I. 95; MFR 5.0;particle size of 100 mesh or less 1.9%; average particle size 310microns) prepared by the prior art process using a catalyst of A-A typetitanium trichloride and diethylaluminum chloride, followed by removalof atactic polymers, and being free from additives were charged in amill pot and subjected to a grinding treatment for 3 hours in anatmosphere of nitrogen.

However, a major part of the polypropylene powder remained under thestate separated from the titanium-containing solid and a homogeneoustitanium-containing solid, as in the case of Example 1-(2) or (3), couldnot be obtained.

EXAMPLE 2

(1) Preparation of titanium-containing solid

25 g (59.2%) of anhydrous magnesium chloride, 8.8 g (20.9%) of anequimolar adduct of titanium tetrachloride and ethyl benzoate and 8.4 g(19.9%) of hexachloroethane were co-ground for 69 hours in an analogousmanner to Example 1-(1) to thus obtain a titanium-containing solidcontaining 2.8% of titanium.

(2) Polymerization grinding treatment

The procedure of Example 1-(2) was repeated except using 40.2 g of thetitanium-containing solid obtained in (1) and adjusting the grindingtime to 1 hour to thus obtain a titanium-containing solid containing6.2% of polypropylene and 2.6% of titanium.

The procedure of the polymerization example in Example 1-(2) wasrepeated except using the titanium-containing solid obtained in thisway. In the polymerization for 30 minutes, there were obtained resultsof C.E. of PP 149 Kg/g-Ti and PP 3880 g/g-catalyst and H.I. of 92.9. Asieve test showed that the product contained 3.2% of a finely powderedpolymer of 100 mesh or less. When the similar operation was carried outby lengthening the polymerization time to 1 hour, C.E. was PP 238Kg/g-Ti and PP 6200 g/g-catalyst and H.I. was 92.0. The amount of a finepowder polymer of 100 mesh or less was 2.9%.

(3) Postgrinding treatment

The mill pot containing 38 g of the titanium-containing solid remainedafter sampling for the above described polymerization test and desiredanalysis was rinsed with nitrogen gas and the grinding treatment wasfurther carried out for 1 hour, thus obtaining a titanium-containingsolid in the form of a very flowable and gray yellow green powder,having a titanium content of 2.4%.

The procedure of the polymerization example in Example 1-(2) wasrepeated except using the titanium-containing solid obtained in thisway. In the polymerization in 30 minutes, there were obtained results ofC.E. of PP 175 Kg/g-Ti and PP 4550 g/g-catalyst and H.I. of 94.1. Asieve test of the polymer showed that the product contained only 0.2% ofa fine powder polymer of 100 mesh or less.

When the similar polymerization was carried out with lengthening thepolymerization time to 1 hour, C.E. amounted to PP 308 Kg/g-Ti and PP8020 g/g-catalyst and H.I. was 93.0 with a slight lowering. The amountof a fine powder polymer of 100 mesh or less was only such as could notbe weighed.

COMPARATIVE EXAMPLE 4

The polymerization test of Example 1-(2) was repeated except using thetitanium-containing solid obtained in Example 2-(1). In thepolymerization in 30 minutes, there were obtained results of C.E. of PP150 Kg/g-Ti and PP 4210 g/g-catalyst, H.I. of 91.8% and 9.2% of a finepowder polymer of 100 mesh or less, and in the polymerization in 1 hour,there were obtained results of C.E. of PP 180 Kg/g-Ti and PP 5052g/g-catalyst, H.I. of 91.0 and 9.0% of a fine powder polymer of 100 meshor less.

As apparent from the above described Example 2 and Comparative Example4, the catalytic activity, stereoregularity and amount of a fine powderpolymer formed are all improved similarly to Example 1, even if the timefor the polymerizing and grinding treatment and the postgrindingtreatment is varied.

EXAMPLE 3

(1) Activation treatment

40 g of the titanium-containing solid (titanium 2.8%) obtained byrepeating the procedure of Example 2-(1) was taken in a 1000 ml glassvessel in an atmosphere of nitrogen. A solution of 80 g ofhexachloroethane in 500 ml of n-heptane was added thereto, treated at120° C. for 2 hours, then cooled at 70° C., filtered to separate thesolution, and the resulting solid was rinsed with fresh n-heptane of 400ml four times at the same temperature, followed by drying at roomtemperature under reduced pressure for 1 hour. The thus obtainedtitanium-containing solid is a light yellow powder containing 1.2% oftitanium.

X-ray diffraction tests of the co-ground products in Example 1-(1)Example 2-(1) showed that the sharp peak of 14.8° (2θ) of anhydrousmagnesium chloride, which had become dull, low and wide, recoveredsomewhat the sharpness by this treatment.

(2) Polymerizing and grinding treatment

The procedure of Example 1-(2) was repeated except using the activatedsolid obtained in (1) to thus obtain a gray yellow green and powderedtitanium-containing solid containing 5.8% of polypropylene and 1.1% oftitanium.

Using the thus resulting titanium-containing solid, the similarpolymerization test was carried out to Example 1-(2). In thepolymerization for 30 minutes, there were obtained results of C.E. of PP195 Kg/g-Ti and PP 2150 g/g-catalyst and H.I. of 97.6. A sieve test ofthe polymer showed that the product contained only 3.2% of a fine powderpolymer of less than 100 mesh. In the polymerization for 1 hour, therewere obtained results of C.E. of PP 304 Kg/g-Ti and PP 3350g/g-catalyst, H.I. of 97.0 and 3.0% of a fine powder polymer of 100 meshor less.

(3) Postgrinding treatment

The procedure of Example 1-(3) was repeated except using thetitanium-containing solid obtained in (2) and adjusting the grindingtime to 1 hour to thus obtain a gray yellow green titanium-containingsolid in the form of a flowable powder.

Using the thus resulting titanium-containing solid, the similarpolymerization test to Examle 1-(2) was carried out. In thepolymerization in 30 minutes, there were obtained results of C.E. of P282 Kg/g-Ti and PP 3100 g/g-catalyst and H.I. of 98.0. The amount of afine powder polymer of 100 mesh or less was only such as could not beweighed. When the polymerization was carried out in the polymerizationtime of 1 hour, there were obtained results of C.E. of PP 493 Kg/g-Tiand PP 5420 g/g-catalyst and H.I. of 97.6.

COMPARATIVE EXAMPLE 5

The procedure of the polymerization example in Example 1-(2) wasrepeated except using the activated titanium-containing solid obtainedin Example 3-(1). In the polymerization in 30 minutes, there wereobtained results of C.E. of PP 200 Kg/g-Ti and PP 2400 g/g-catalyst andH.I. of 97.4. A sieve test of the polymer showed that the productcontained 9.3% of a finely powdered polymer of 100 mesh or less. In thepolymerization in 1 hour, there were obtained results of C.E. of PP 240Kg/g-Ti and PP 2880 g/g-catalyst, H.I. of 97.0 and 8.9% of a fine powderpolymer of 100 mesh or less.

EXAMPLE 4

(1) Preparation of titanium-containing solid

20 g of anhydrous magnesium chloride, 6.3 g of ethyl benzoate and 4.6 gof silicon tetrachloride were charged in the shaking mill pot used inExample 1-(1) and subjected to a grinding treatment for 30 minutes toobtain a supported composition. 30 g of this supported composition wasplace in a schlenk tube of 200 ml, to which 150 ml of titaniumtetrachloride was added. The mixture was contacted under boiling for 2hours, cooled to 70° C., filtered to separate the solution and theresidual solid was rinsed five times with 150 ml of n-heptane, followedby drying under reduced pressure, thus obtaining a powderedtitanium-containing solid containing 1.6% of titanium.

(2) Polymerizing and grinding treatment

The procedure of Example 1-(2) was repeated except using 28 g of thetitanium-containing solid obtained in (1) to thus obtain a powderedtitanium-containing solid containing 1.3% of titanium and 6.8% ofpolypropylene.

Using the titanium-containing solid obtained in this way, thepolymerization test was carried out in the manner of Example 1-(2). Thepolymerization was run for 30 minutes. The results obtained were C.E. ofPP 112 Kg/g-Ti and PP 1460 g/g-catalyst, H.I. of 93.5 and 2.9% of a finepowder polymer of 100 mesh or less. In a second polymerization run for 1hour, there were obtained results of C.E. of PP 174 Kg/g-Ti and PP 2260g/g-catalyst, H.I. of 93.0 and 2.8% of a fine powder polymer of 100 meshor less.

(3) Postgrinding treatment

The procedure of Example 2-(3) was repeated except using 25 g of thetitanium-containing solid obtained in (2) and adjusting the grindingtime to 1 hour, thus obtaining a flowable titanium-containing solidsubstantially free from fine particles.

Using the titanium-containing solid obtained in this way, the similarpolymerization test to Example 1-(2) was carried out. After 30 minutesof polymerization, there were obtained results of C.E. of PP 150 Kg/g-Tiand PP 1950 g/g-catalyst, H.I. of 94.2 and 2.1% of a finely powderedpolymer of less than 100 mesh and in the polymerization for 1 hour,there were obtained results of C.E. of PP 234 Kg/g-Ti and PP 3040g/g-catalyst, H.I. of 93.8 and 1.8% of a fine powder polymer of lessthan 100 mesh.

COMPARATIVE EXAMPLE 6

The polymerization test of Example 1-(2) was repeated except using thetitanium-containing solid obtained in Example 4-(1). For thepolymerization in 30 minutes, there were obtained results of C.E. of PP113 Kg/g-Ti and PP 1800 g/g-catalyst, H.I. of 93.4 and 12% of a finepowder polymer of less than 100 mesh and for the polymerization in 1hour, there were obtained results of C.E. of PP 124 Kg/g-Ti and PP 1975g/g-catalyst, H.I. of 93.0 and 11.5% of a fine powder polymer of lessthan 100 mesh.

EXAMPLE 5

(1) Preparation of titanium-containing solid

34.0 g of anhydrous magnesium chloride, and 10.3 g of an equimolaradduct of titanium tetrachloride and ethyl benzoate were used andco-ground for 64 hours in an analogous manner to Example 1-(1) to thusobtain a titanium-containing solid containing 3.0% of titanium. X-raydiffraction analysis of the solid showed that the peaks of 14.8° and50.3° of the characteristic peaks (2θ) of anhydrous magnesium chloridebecame dull with increased widths and the peaks of 30.2°, 34.8° and 63°disappeared.

(2) Polymerizing and grinding treatment

The procedure of Example 2-(2) was repeated except using 43.0 g of thetitanium-containing solid obtained in (1) to thus obtain atitanium-containing solid containing 5.2% of polypropylene and 2.8% oftitanium.

The polymerization test of Example 1-(2) was repeated except using thethus resulting titanium-containing solid. In the polymerization in 30minutes, there were obtained results of C.E. of PP 120 Kg/g-Ti and PP3350 g/g-catalyst and H.I. of 90.2 and in the polymerization in 1 hour,there were obtained results of C.E. of PP 163 Kg/g-Ti and PP 4560g/g-catalyst and H.I. of 90.0. The amounts of fine powder polymers wererespectively 7.4% and 7.0%, the fine powder having a particle size of100 mesh or less.

(3) Postgrinding treatment

The procedure of Example 2-(3) was repeated except using 40.0 g of thetitanium-containing solid obtained in (2) to thus obtain atitanium-containing solid containing 2.8% of titanium.

Then, the polymerization test of Example 1-(2) was repeated except usingthe titanium-containing solid obtained in this way. In thepolymerization in 30 minutes, there were obtained results of C.E. of PP124 Kg/g-Ti and PP 3480 g/g-catalyst and H.I. of 88.9 and in thepolymerization in 1 hour, there were obtained results of C.E. of PP 175Kg/g-Ti and PP 4900 g/g-catalyst and H.I. of 88.0. The amounts of finepowder polymers of 100 mesh or less were respectively 6.4% and 6.3%.

COMPARATIVE EXAMPLE 7

The procedure of the polymerization example of Example 1-(2) wasrepeated except using the titanium-containing solid obtained in Example5-(1). In the polymerization in 30 minutes, there were obtained resultsof C.E. of PP 95 Kg/g-Ti and PP 2860 g/g-catalyst and H.I. of 82.2 andin the polymerization in 1 hour, there were obtained results of C.E. ofPP 97 Kg/g-Ti and P 2920 g/g-catalyst and H.I. of 81.5. In this case,the value of H.I. is low, i.e., there is a large amount of atacticpolymers, so the flowability of the polymer is not good and a sieve testcomparable with Examples cannot be carried out.

EXAMPLE 6

Copolymerization of ethylene and propylene

29.3 mg of the titanium-containing solid obtained in Example 2-(3), 0.98g of triisobutylaluminum and 0.22 g of ethyl benzoate were mixed, heldfor 5 minutes and charged in an autoclave with a capacity of 1000 ml,equipped with a stirrer, to which 0.6 l of H₂ and 0.8 l of liquidpropylene were added, followed by raising the temperature to 68° C. andpolymerizing for 60 minutes. During the same time, 4.5 g of ethylene gaswas forcedly introduced into the autoclave under pressure three timesevery 10 minutes. Thus, there were obtained results of C.E. of copolymer415 Kg/g-Ti and copolymer 9970 g/g-catalyst, H.I. of copolymer of 85 andethylene content 3.1%. According to a sieve test of the polymer,formation of a fine powder polymer of 100 mesh or less was negligible.

What is claimed is:
 1. A titanium-containing solid catalyst component for use in the polymerization of α-olefins, which is produced by a process comprising:(a) adding an organo aluminum catalyst component selected from organo aluminum compounds and mixtures of organo aluminum compounds and electron donative compounds to a supported titanium (IV) halide on a magnesium halide; (b) subjecting the mixture to a mechanical grinding treatment in the presence of an ethylenically unsaturated hydrocarbon until the intensity of magnesium halide x-ray diffraction peak at 14.8° is dull and the intensity of the 30.2° peak is reduced; and (c) recovering the resulting titanium-containing solid catalyst component.
 2. The solid catalyst component of claim 1 wherein the recovered titanium-containing solid catalyst component is subjected to further mechanical grinding.
 3. The solid catalyst component of claim 1, wherein the ethylenically unsaturated hydrocarbon is diluted with an inert gas and/or inert solvent.
 4. The solid catalyst component of claim 2, wherein the further mechanical grinding treatment is carried out in the presence of an inert gas and/or inert solvent.
 5. The solid catalyst component of claim 4, wherein the further mechanical grinding treatment is carried out in the presence of an inert gas.
 6. The solid catalyst component of claim 1, wherein the supported titanium (IV) halide on magnesium halide comprises a mixture of magnesium halide, a tetravalent titanium halide, a Lewis base and a halogen compound selected from halogen-substituted hydrocarbons, halogen-substituted oxygen-containing organo compounds and halogen-containing compounds of Group IVa elements selected from the group consisting of Si_(q) X_(2q+2), GeX_(m), SnX_(m) and PbX_(m), wherein X is a halogen, alkyl, aryl, aralkyl, vinyl, alkoxy and acyl group, at least one X being halogen, q is an integer of from 1 to 10 and m is an integer of from 1 to
 4. 7. The solid catalyst component of claim 6, wherein the halogen compound is a halogen-substituted hydrocarbon.
 8. The solid catalyst component of claim 7, wherein the halogen-substituted hydrocarbon is a polychloro aliphatic hydrocarbon having from 1 to 4 carbon atoms.
 9. The solid catalyst component of claim 8, wherein the polychloro-substituted aliphatic hydrocarbon is selected from the group consisting of carbon tetrachloride, 1,1,2-trichloroethylene, 1,1,2,2-tetrachloroethane, hexachloroethane and octachloropropane.
 10. The solid catalyst component of claim 9 wherein the polychloro-substituted hydrocarbon is hexachloroethane.
 11. The solid catalyst component of claim 1, wherein the ethylenically unsaturated hydrocarbon is selected from the group consisting of ethylene and α-olefins having from 3 to 20 carbon atoms.
 12. The solid catalyst component of claim 6, wherein the Lewis base is an organic acid ester of a saturated or unsaturated aliphatic, alicyclic and aromatic mono- or polycarboxylic acid and an aliphatic, alicyclic and araliphatic mono- or polyol.
 13. The solid catalyst component of claim 12, wherein the Lewis base is an alkyl ester of an aromatic carboxylic acid.
 14. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 1. 15. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 2. 16. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 3. 17. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 4. 18. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 5. 19. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 6. 20. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 7. 21. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 8. 22. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 9. 23. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 10. 24. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 11. 25. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 12. 26. A catalyst system for use in the polymerization of α-olefins comprising a mixture of:(a) an organo aluminum catalyst component comprising an organo aluminum compound and a Lewis base; and (b) the titanium-containing solid catalyst component of claim
 13. 